Integration of Optical Metamaterials on Curved Surfaces for Non‐Contact Temperature Sensing

ABSTRACT (Optical metamaterials like metalenses and metasurfaces show great potential for light manipulation. Their fabrication via integrated‐circuit‐compatible processes enables applications in quantum information processing, super‐resolution imaging, and AR/VR displays, though most realized integrated metamaterials remain passive. Here, we report an active dynamic optical metamaterial that enables real‐time tuning of the metamaterial's optical properties via thermal effects such as the thermal reflow effect, facilitating non‐contact temperature monitoring on object surfaces. This study utilizes PDMS‐assisted nanoimprint lithography to integrate diffractive optical elements (DOEs) on the chip. Differential light efficiencies across various diffraction orders are obtained when the sample is heated above the diffractive grating material's glass transition temperature. Specifically, the ratio of ±first‐order diffraction efficiencies shift from 5:1 to 1:1, while the 0 th ‐order diffraction efficiency exhibits a 70% change. Thermal imaging mapping is subsequently conducted employing dynamically generated two‐dimensional (2‐D) diffraction patterns, facilitating large‐scale, real‐time, and precise non‐contact temperature monitoring of objects. This work has provided an alternative route for real‐time mapping of surface temperature without the need for characterization of material's thermal emission coefficient. It can potentially be used in studying the thermal distribution of a packaged semiconductor chip as well as monitoring the threshold temperature of any DOE‐integrated industrial surfaces).